Your quote showed up by mistake.That thing might be a vent, or maybe a lint trap of some kind?
Change your supply hoses to burst proof braided type.
I don’t have arrestors at my house. 21 yrs, no problem so far. Copper tube and 80 psi. 90psi early in the morning.That's another good point, sawguy.
Jeff, Thanks! We plan to replace the supply hoses. Not sure if we already bought some, but I will look for the braided steel ones.
Btw, are hammer arrestors still necessary on the shutoffs? I've seen some say they are no good and others say they are needed.